in vitro study nonhuman 283 article 274 controlled study 257 priority journal 218 Animals 207 animal experiment 191 human 152 unclassified drug 144 animal cell 135 animal 131 metabolism 130 Female 121 Animal 119 Humans 117 rat 115 mouse 108 female 106 human cell 106 Article 104 Male 104 Rats 103 Mice 100 in vivo study 93 male 90 protein expression 74 animal tissue 71 theoretical study 66 animal model 65 Support, Non-U.S. Gov't 57